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Hydrothermal synthesis of lithium silicate from waste glass. A preliminary study

Coleman N. J., Hurt A. P., Raza A.

Physicochemical Problems of Mineral Processing

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2015

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Vol. 51, iss. 2

685--694

EN

Current environmental directives to conserve resources and to divert waste streams have generated significant interest in mineral recycling. In this respect, this preliminary study has demonstrated that lithium metasilicate can be prepared by hydrothermal reaction between waste container glass and lithium hydroxide solutions at 100 °C. Minor proportions of calcium hydroxide, calcite, lithium carbonate and tobermorite were also produced during the reaction. Percentage crystallinity and proportion of lithium metasilicate in the reaction product were found to increase as functions of lithium hydroxide concentration (between 1 and 4 M). This research has also shown that the lithium metasilicate phase can take up 6.4 mmol/g of Zn2+ ions after 24 h during batch sorption. Further work to optimise the yield and to appraise the antimicrobial properties of Zn2+-bearing lithium metasilicate is now warranted.

2

Synthesis, structure and performance of calcium silicate ion exchangers from recycled container glass

Coleman N. J., Li Q., Raza A.

Physicochemical Problems of Mineral Processing

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2014

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Vol. 50, iss. 1

5--16

EN

Numerous technical, economic and societal factors limit the recycling of waste soda-lime-silica glass back into the primary production process and accordingly alternative applications for this material are sought. This study demonstrates that waste soda-lime-silica container glass is a suitable feedstock material for the production of tobermorite, a calcium silicate cation exchanger. Tobermorites were synthesised at 100 °C from stoichiometric mixtures of container glass and lime under alkaline hydrothermal conditions. Increasing concentrations of sodium hydroxide (between 1.0 M and 4.0 M) in the reaction mixture promoted the formation and crystallisation of tobermorite, and also resulted in greater fragmentation of the silicate chains along the b-axis direction. The maximum removal capacities of these tobermorite specimens for Cd2+ (441 mg g-1) and Zn2+ (122 mg g-1) compared well with those of other waste-derived sorbents. Superior Cd2+- and Zn2+-uptake capacities and kinetics were observed for the least crystalline tobermorite specimen, indicating that stacking defects facilitate the transport and exchange of cations within the lattice.

3

Spectrophotometric determination of amodiaquinone and sulfadoxine in pharmaceutical preparations

Ansari M. T., Ansari T. M., Raza A., Ashraf M., Yar M.

Chemia Analityczna

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2008

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Vol. 53, No. 2

305-313

EN

A new rapid and sensitive spectrophotometric method was developed for the determination of amodiaquine and sulfadoxine in both pure and dosage forms. The proposed method is based upon the reaction of amino group with sodium nitrite followed by β-naphthol that produces a colored compound. These species exhibit the maximum absorption at 505 nm for amodiaquine and at 470 nm for sulfadoxine with molar absorptivity of 6.83 x 104<.sup> and 3.74 x 104 L mol-1 cm-1 respectively. The range of linearity for the both drugs is 4-60 μg mL-1. The optimum reaction conditions and other analytical parameters have also been investigated. The influence of substrates commonly employed as excipients with these drugs have been studied. The proposed method is applicable for the determination of these drugs in pharmaceutical formulations. The results demonstrated that the method is accurate, reproducible and comparable to the official method.

PL

Opracowano nową szybką i czulą spektrofotometryczną metodę oznaczania amodiachiny i sulfadioksyny w czystej postaci i w lekach. Metoda polega na reakcji grupy aminowej z azotanem(III) sodu, a następnie z p-naftolem, w wyniku której powstaje barwny produkt. Maksima absorpcji wy stępuj ą odpowiednio przy 505 nm i 470 nm, a współczynniki absorpcji wynoszą odpowiednio: 6.83 x 104<.sup> i 3.74 x 104 L mol-1 cm-1 dla amodiachiny i sulfadioksyny. W przypadku obu leków zakres stosowalności prawa Beera wynosi od 4 do 60 μg mL-1. Zbadano optymalne warunki oznaczenia i wpływ substancji mogących występować w lekach. Metoda może być stosowana do oznaczania leków w preparatach farmaceutycznych. Otrzymane wyniki wskazują, że metoda jest dokładna, odtwarzalna i porównywalna z oficjalnie stosowanymi metodami.